Case IH 3513-04 - DEC – Engine Control Unit (ECU / ECM): Sensor Supply 5 Circuit - Voltage Below Normal or Shorted to Low Source

The Engine Control Module (ECM) has detected the sensor supply voltage is out of range low. The supply circuit providing reference voltage to engine sensors has dropped below the acceptable threshold, almost always due to a short circuit to ground in the OEM harness or an internally shorted sensor.

• MAGNUM AFS Connect
• CVX (140, 150, 160, 175, 195)
• Magnum series
• Steiger tractors

1. 1

   Check the main battery voltage to ensure the system is receiving proper base voltage.

2. 2

   Inspect the sensor supply harnesses and connections originating from the ECU/ECM for obvious signs of chafing, rubbing, or bare wires.

3. 3

   Test the sensor supply circuit for a potential short-circuit to ground.

4. 4

   Identify which sensors are powered by this specific supply instance. In many Case IH/CNH applications, SPN 3513 is tied to the EGR (Exhaust Gas Recirculation) valve position sensor or aftertreatment sensors. Check the EGR (M38) actuator for internal shorts.

1. 1

   Verify active fault

   Turn the keyswitch to the ON position to verify if the fault code is currently active. (The engine will likely be in a Limp Home / severe derate mode).

2. 2

   Disconnect sensors

   Disconnect the sensors powered by this specific supply circuit one at a time.

3. 3

   Test for shorted sensor

   Monitor the circuit voltage with a multimeter or observe the active fault codes on your electronic service tool. If the voltage returns to normal (or the code goes inactive) after unplugging a specific sensor, that sensor is internally shorted to ground and must be replaced.

4. 4

   Trace wiring harness

   If unplugging the sensors does not resolve the low voltage, use a multimeter to trace the OEM wiring harness back to the ECU to locate the short to ground.

5. 5

   Repair or replace harness

   Repair the damaged section of the wiring harness or replace the harness entirely.

6. 6

   Validate repair

   To validate the repair, perform a key cycle, start the engine, and let it idle for at least 1 minute. The fault code status should change to INACTIVE, and the ECU will turn off the amber CHECK ENGINE lamp. You may need to use an electronic service tool to clear the inactive code from the module's history.